Abstract: OBJECTIVE To observe the effect of estrogen on H2O2-induced apoptosis and to study the protection of estrogen. METHODS Setting up the experimental model of apoptosis induced by H2O2 in PC12 cells. The viability of cells was assessed by MTT assay. The activity of lactate dehydrogenase was detected by colorimetry. Hoechst 33258 was used to show apoptosis. The percent of apoptotic cells was measured by flow cytometry (FCM) with propidium iodide stain. The activity of caspase-3 was detected by colorimetry. RESULTS H2O2 significantly decreased the viability of cell, increased leakage of LDH, and promoted apoptosis as well as caspase-3 activity in PC12. Estrogen markedly reduced these changes. CONCLUSIONS Estrogen reduce apoptosis induced by H2O2, and its mechanisms may involve inhibition of activation of caspase-3.

Key words: estrogen, hydrogen peroxide, apoptosis, caspase-3